Recent research has reported that HSP72 released from tumor cells on surface of exosome. Therefore, we aimed to assess the NHq method, which we established method to isolate of HSP72-binding proteins, for purification of exosome and to explore for biomarker. HSP72-binding molecules isolated with NHq could not involve CD63 and CD9. These markers of exosome were detected in flow-through of NHq method. HSP72 was mainly detected in the supernatant of ultracentrifugation. HSP72 did not exist on surface of exosome against previous report. Therefore, we concluded that NHq method could not isolate exosome. Whereas, we tried to explore the biomarker of multiple myeloma using NHq method. As a result, we identified 3 proteins in sera of patients. One of these proteins might be a biomarker of multiple myeloma.